There have been various proposals regarding a low pressure casting method, wherein a molten metal is pressurized and filled into a cavity of a gypsum mold through a pipe so as to perform casting.
Thus, for example, Japanese Patent Application Laid-open Publication No. 61-95760 discloses a method wherein the inner space of the gypsum mold is subjected to pressure reduction so as to suck a molten metal. In this instance, the molten metal is allowed to cool after it has solidified in the mold cavity, and the cast metal is removed from the mold after it completion of the cooling.